1. Field of the Invention
The present invention relates to a medical handpiece, and especially a dental handpiece, including a drivable worktool or implement which is rotatably supported with its shaft at one end of the handpiece and which projects from this handpiece end with its operating end. The implement possesses an elongate blind bore-like passageway which communicates with the outside at the work end of the implement through the intermediary of a discharge opening, and with which there is associated a supply line arranged within the handpiece for the infeed of cooling media to at least one radial through-opening of the implement which stands in communication with the elongate passageway; whereby the at least one radial through-opening is sealed with respect to the interior of the handpiece through the intermediary of a seal which encompassing the shaft of the implement and contacts against a wall portion of the handpiece.
2. Discussion of the Prior Art
A dental handpiece of this type has already become known from the disclosure of German Pat. No. 34 33 570. In this known handpiece, the sealing device which is constructed in the form of a sealing ring encompasses the implement shaft in an axially movable manner such that, during the movement of the implement out of the handpiece; for instance; for the purpose of exchanging the implement, the sealing ring which axially contacts from above against the wall portion of the handpiece, remains within the handpiece so as to practically form a fixed component of the handpiece. As a consequence thereof, during the cleaning or respectively the sterilizing of the handpiece, because of the implement receiving opening of the handpiece being exposed or open as a result of the withdrawal of the implement, the relatively aggressive cleaning or sterilizing fluid penetrates into the handpiece and attacks the sealing ring, as a result of which the last-mentioned becomes brittle or flawed through this influence thereon and loses its sealing effect. Hereby, in that the sealing ring remains positioned within the handpiece in this known handpiece construction, it is not possible to exchange the sealing ring without any disassembling of the handpiece.